Yu-Gi-Oh! 7 Trials to Glory

If you haven't beaten the game, the color of the Title Screen is normally blue. But after you win the game, the color switches to purple. You can change it back to blue by pressing Up, Up, Down, Down, Left, Right, Left, Right, B, A at the title screen. Input the same code to change it back to purple.

Make an Exodia deck your current deck. Go to the card shop. Chat to Grampa and he will ask you to duel against him using an Exodia deck. Both of the lifepoint scores will start at 10. The only way to win is to get all five pieces of Exodia into your hand. Bringing either players' lifepoints to zero will end the duel in a tie.